Bacterial infections continue to remain one of the major causes contributing towards human diseases. One of the key challenges in treatment of bacterial infections is the ability of bacteria to develop resistance to one or more antibacterial agents over time. Examples of such bacteria that have developed resistance to typical antibacterial agents include: Penicillin-resistant Streptococcus pneumoniae, Vancomycin-resistant Enterococci, and Methicillin-resistant Staphylococcus aureus. The problem of emerging drug-resistance in bacteria is often tackled by switching to newer antibacterial agents, which can be more expensive and sometimes more toxic. Additionally, this may not be a permanent solution as the bacteria often develop resistance to the newer antibacterial agents as well in due course. In general, bacteria are particularly efficient in developing resistance, because of their ability to multiply very rapidly and pass on the resistance genes as they replicate.
Treatment of infections caused by resistant bacteria remains a key challenge for the clinician community. One example of such challenging pathogen is Acinetobacter baumannii (A. baumannii), which continues to be an increasingly important and demanding species in healthcare settings. The multidrug resistant nature of this pathogen and its unpredictable susceptibility patterns make empirical and therapeutic decisions more difficult. A. baumannii is associated with infections such as pneumonia, bacteremia, wound infections, urinary tract infections and meningitis.
Therefore, there is a need for development of newer ways to treat infections that are becoming resistant to known therapies and methods. Surprisingly, it has been found that a compositions comprising imipenem and certain nitrogen containing bicyclic compounds (disclosed in PCT/IB2012/054706) exhibit unexpectedly synergistic antibacterial activity, even against highly resistant bacterial strains.